With the increasing popularization of the device with a large screen, more and more users will utilize the device with a large screen. However, when the device with a large screen is utilized, the user usually can′ utilize all of the touch and display area of the device since the operation range of the screen is large enough. Thus, it is necessary for the user to display a file selected by the user at a corresponding displaying position for the user's operation. In turn, it is necessary for the user to manually operate to select the file and to select the displaying position. When it is impossible for the user to reach the displayed position of the file, there will be a problem in which the user can't operate the file.